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Aviation History
1979
1979 - 1798.PDF
straighter jetpipe. Although many of the original Handley Page drawings were saved when that company folded, few of the stress calculations remain and these are having to be reworked at Prestwick—a limiting factor in the development process at present be cause of the group-wide shortage of engineering staff. Chalmers explains that his design team is not setting about a dramatic weight-reduction programme. They are looking at details as they emerge, and changes may come along once the aircraft is established in production. Indeed, the concept is for now one of minimum change, and the first ten production aircraft off the line will have only the changes to be associ ated with the basic Series 31 design. British Aerospace is advised by its Washington sales office to be ready for deliveries in 1981, and it does not intend to allow detail improvements to prejudice that target. From divisional managing director Lynn Phillimore I learn that the prime target is to be the American com muter market—hence this version, the 3101. The 3102 will be the equivalent non-American specification; corporate versions will become the 3103 (US) and 3104 (rest of the world). Produc tion is planned to be built up to 25 aircraft/year by 1982, a figure con ditioned largely by material avail ability for long-lead items. Phillimore agrees that the market might easily sustain a higher production rate, but he claims that a decision to increase is not critical for the moment. "A decision before March 1981 will be 1720 early enough for us to continue the build-up. The last thing I want for this factory is a cyclical climate in which one minute we're hiring and the next minute we're trying to avoid firing. We must watch for an over shoot of manpower in building up the production rate." During Scottish Aviation's owner ship of the Jetstream programme there was a dearth of research and development, The pre-nationalisation owners did not invest in either de velopment or demonstration aircraft, and this meant in practice that only work related directly to military Jet- streams could be undertaken—and then only by retaining a military example at the factory. One small success that will be carried forward is that Scottish managed to make the stall repeatable and hence a bit more predictable than had been the case with early production examples, British Aerospace does not now intend to alter the centre^of-gravity range or otherwise try to simplify the stall pro tection; it will keep the relatively com plex but proven stick pusher. Simi larly, the characteristic nose-up Jet stream "sit" will almost certainly continue. "Some tuning may be pos sible in the future," says Chalmers, "but it's really a basic wing/tailplane relationship problem." We talk of some changes that are firm. The flight deck will be restyled and there is a fundamental rethink of the electrical system. This has not yet reached a conclusion, and the produc tion aircraft may yet emerge with any combination of AC or DC power. To tide the development aircraft over, a satisfactory blend of new engines and old electrics has been achieved. Plessey has offered a starter/generator that is currently mocked up on the trial engine installation. It may not be the final answer, but it has the attrac tion that Plessey has a tie-up with Westinghouse to support its products in the Americas. The original Vickers/Sperry Rand hydraulic pump is no longer available, and the choice lies between an up dated unit from the same source or one from German supplier Abex. The cold-air units, likewise, -ire no longer in production. In any case the bleed RIGHT International, It May 1979 air from the Garrett is hotter than that from the Astazou and will neces sitate a pre-cooler in the environ mental system. Normalair-Garrett is holding urgent discussions about new units and controllers, and the air frame manufacturer is taking a close look at the main door seal—Achilles heel of the Jetstream's pressurisation because of its excessive leakage. Scottish Division feels that the basic door mechanism is good, but some form of inflatable seal is almost certain to be adopted. While few changes are necessary for the undercarriage—again a unit which has been proved at Series 3M weight —Chalmers feels that more brake capacity would be worthwhile. He is studying offers from several suppliers but notes that the Goodyear adaptive anti-skid system appears to be particu larly suitable. This could help to reduce balanced field length, and another approach to this problem may be by scheduling take-off with either 10° or 20° flap settings, allowing the operator the optimum choice. It is accepted that the choice of avionics must remain with the buyer, but British Aerospace will try to narrow the choice and a "standard" aircraft is foreseen. Collins and Sperry are competing to supply the flight system, the former stressing its ability to supply virtually all avionics, while the latter points out that its SPZ-200 flight-control system is compatible with any manufacturer's navigation receivers and attitude inputs. Jetstream marketing to the com muters is to be through Washington, which will shortly appoint approved fitting-out centres in the United States. By the time a green aircraft from Prestwick has been furnished and painted in the United States, the American content will be exactly half of the total value; older, Astazou- powered Jetstreams amounted to about 38 per cent American content. The price of an equipped commuter is to be $1-3 million at 1979 values, while the European price of a cor porate Jetstream will be £750,000. British Aerospace has not asked potential buyers to harden up their options yet, but there are firm pros pects of American sales. As other would-be importers into the United States have found, British Aerospace had to have an American purchase option before the Federal Aviation Administration would begin talks about certification. These talks are now well advanced, and the FAA is being particularly helpful. British Aerospace commitment to Jetstream is complete, and the pro gramme is being funded by the cor poration. It offers long-term stability to the Scottish Division. Top A mock-up starter/generator has been installed beneath the engine. Wooden frames are being used to arrive at the final contour of the cowling. Left High mounting of the Garrett engine allows a straight jetpipe over the wing
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